(a) In any prosecution for theft or extortion it is an affirmative defense that the property was appropriated by the actor under a claim of right, made in good faith, to do substantially what the actor did in the manner in which it was done.
(b) In any prosecution for extortion where the facts are as described in § 846(4) of this title, it is an affirmative defense that the accused believed the threatened criminal charge to be true and that the accused's sole purpose was to compel or induce the victim to take reasonable action to make good the wrong which was the subject of the threatened charge.